ABSTRACT Previous investigations of mechanical squeezing have primarily been concentrated on a single manipulation method. We propose an innovative scheme to address the research gap by leveraging the synergy of an optical Kerr media and mechanical parametric amplification (MPA) in an optomechanical system to efficiently generate strong mechanical squeezing. By reasonably choosing the system parameters, this scheme has the following outstanding advantages: the squeezing effect of the cavity field induced by the optical Kerr medium can be transferred to the mechanical oscillator, which has been squeezed by the mechanical parametric amplifiers. The squeezing of the mechanical oscillator is higher than that of either state alone, and through this joint effect the squeezing can be significantly increased, ultimately realizing a strong mechanical squeezing. The scheme also exhibits notable robustness against both thermal noise and decay of the mechanical oscillator. The presented scheme provides an efficient and experimentally feasible platform for achieving strong mechanical squeezing, paving the way for generating other quantum effects.
ABSTRACT Previous investigations of mechanical squeezing have primarily been concentrated on a single manipulation method. We propose an innovative scheme to address the research gap by leveraging the synergy of an optical Kerr media and mechanical parametric amplification (MPA) in an optomechanical system to efficiently generate strong mechanical squeezing. By reasonably choosing the system parameters, this scheme has the following outstanding advantages: the squeezing effect of the cavity field induced by the optical Kerr medium can be transferred to the mechanical oscillator, which has been squeezed by the mechanical parametric amplifiers. The squeezing of the mechanical oscillator is higher than that of either state alone, and through this joint effect the squeezing can be significantly increased, ultimately realizing a strong mechanical squeezing. The scheme also exhibits notable robustness against both thermal noise and decay of the mechanical oscillator. The presented scheme provides an efficient and experimentally feasible platform for achieving strong mechanical squeezing, paving the way for generating other quantum effects.
We propose a proposal to achieve strong mechanical squeezing in an optomechanical system through the joint effect of a weak squeezed vacuum field and Duffing nonlinearity. The squeezing of the cavity field induced by the squeezed vacuum field is transferred to the mechanical oscillator, which has already been squeezed via Duffing nonlinearity. This joint effect significantly enhances the degree of mechanical squeezing, enabling it to exceed the 3 dB strong mechanical squeezing limit. Moreover, the resulting mechanical squeezing exhibits remarkable robustness against thermal noise. The joint effect proposed in this scheme can be directly observed through homodyne detection of the cavity output field. This novel approach opens up a new avenue for generating a strong mechanical squeezed state and provides a promising pathway for the applications of macroscopic quantum control in quantum sensing and quantum information processing.
The photon blockade effect, as a quantum behavior in cavity optomechanics, has certain limitations, including stringent requirements for system parameters and technical difficulties in achieving strong nonlinear interactions. This paper proposes a novel scheme that aims to achieve strong nonlinear effects through introducing the degenerate optical parametric amplifier (OPA) and mechanical squeezing. These enhanced nonlinear effects can significantly improve the photon blockade effect, effectively overcoming the limitations of weak coupling. Our theoretical analysis demonstrates the successful realization of an ideal single-photon blockade (1PB) state through optimized parameter conditions. Additionally, this joint approach significantly enhances the two-photon blockade (2PB) effect and broadens the region where 2PB occurs. This finding helps us identify the optimal system parameters to maximize two-photon emission efficiency. By precisely controlling these parameters, a new pathway is opened for more flexible manipulation and utilization of the photon blockade effect in experiments.
The nonlinear quantum regime is crucial for implementing interesting quantum effects, which have wide applications in modern quantum science. Here we propose an effective method to reach the nonlinear quantum regime in a modulated optomechanical system (OMS), which is originally in the weak-coupling regime. The mechanical spring constant and optomechanical interaction are modulated periodically. This leads to the result that the resonant optomechanical interaction can be effectively enhanced into the single-photon strong-coupling regime by the modulation-induced mechanical parametric amplification. Moreover, the amplified phonon noise can be suppressed completely by introducing a squeezed vacuum reservoir, which ultimately leads to the realization of photon blockade in a weakly coupled OMS. The reached nonlinear quantum regime also allows us to engineer the nonclassical states (e.g., Schr\"odinger cat states) of the cavity field, which are robust against the phonon noise. This work offers an alternative approach to enhance the quantum nonlinearity of an OMS, which should expand the applications of cavity optomechanics in the quantum realm.
We propose an alternative experimentally feasible approach to achieve high-efficiency ground-state cooling of a mechanical oscillator in an optomechanical system under the deeply unresolved sideband condition with the assistance of both intracavity and extracavity squeezing. In the scheme, a degenerate optical parametric amplifier is placed inside the optical cavity, generating the intracavity squeezing; in addition, the optical cavity is driven by the extracavity squeezed light, namely the extracavity squeezing. The quantum interference effect generated by intracavity squeezing and extracavity squeezing can completely suppress the nonresonant Stokes heating process while greatly enhancing the anti-Stokes cooling process. Therefore, the joint-squeezing scheme is capable of cooling the mechanical oscillators to their quantum ground state in a regime far away from the resolved sideband condition. Compared with other traditional optomechanical cooling schemes, the single-photon cooling rate in this joint-squeezing scheme can be tremendously enlarged by nearly three orders of magnitude. At the same time, the coupling strength required to achieve ground-state cooling can be significantly reduced. This scheme is promising for cooling large-mass and low-frequency mechanical oscillators, which provides a prerequisite for preparing and manipulating nonclassical states in macroscopic quantum systems and lays a significant foundation for quantum manipulation.
Previous works for achieving mechanical squeezing focused mainly on the sole squeezing manipulation method. Here we study how to construct strong steady-state mechanical squeezing via the joint effect between Duffing nonlinearity and parametric pump driving. We find that the 3 dB limit of strong mechanical squeezing can be easily overcome from the joint effect of two different below 3 dB squeezing components induced by Duffing nonlinearity and parametric pump driving, respectively, without the need of any extra technologies, such as quantum measurement or quantum feedback. We first demonstrate that, in the ideal mechanical bath, the joint squeezing effect just is the superposition of the two respective independent squeezing components. The mechanical squeezing constructed by the joint effect is fairly robust against the mechanical thermal noise. Moreover, different from previous mechanical squeezing detection schemes, which need to introduce an additional ancillary cavity mode, the joint mechanical squeezing effect in the present scheme can be directly measured by homodyning the output field of the cavity with an appropriate phase. The joint idea opens up a new approach to construct strong mechanical squeezing and can be generalized to realize other strong macroscopic quantum effects.
Realization of quantum nonlinearity in quadratic optomechanics, including optical and mechanical nonlinearity at the single-photon level, is crucial to explore extraordinary quantum features. Here we investigate an exponential enhancement of quadratic optomechanical interaction via parametric amplifications. The parametric process can form an in-phase amplified quadrature, and the rate of coupling to the in-phase quadrature will be exponentially increased even to the single-photon strong-coupling regime. Concretely, to achieve the optical nonlinearity mediated by the quadratic optomechanical interaction, we can employ a mechanical parametric process, and the in-phase mechanical quadrature can strongly couple to the cavity mode, leading to an enhanced optical nonlinearity such as a photon blockade. Similarly, via employing the optical parametric process, the in-phase optical quadrature can also effectively mediate the quadratic interaction, leading to an enhanced mechanical nonlinearity such as mechanical squeezing, bi-excitation exchange interaction and feasibility of quantum non-demolition detection of mechanical motion. However, the parametric process can also enlarge the noise, and a squeezing vacuum with the phase matching condition should be introduced to suppress the same.